1. Field of the Invention
The present invention relates to a substrate comprising a light reflection pattern for reflecting a light from a light source. The present invention further relates to an image recording apparatus using the substrate.
2. Description of the Related Art
As described in U.S. Pat. No. 4,734,704, a heat-sensitive recording material in which a magenta heat-sensitive coloring layer, a cyan heat-sensitive coloring layer and a yellow heat-sensitive coloring layer are sequentially laminated on a backing has been developed. Microcouples containing each coloring agent are dispersed in a respective coloring layer. Each coloring layer has a respective different coloring heat energy in this heat-sensitive recording material. Therefor it is possible to develop each color by providing a different heat energy on a respective coloring layer. Then, before a lower coloring layer is printed after an upper coloring layer is printed, the printed coloring layer is fixed by a wavelength light, for example, ultraviolet ray radiation, specific for the printed layer. This processing is called photo-fixing. The printing system using the above heat-sensitive recording material is called Thermo-Autochrom system.
The heat-sensitive recording material of the above Thermo-Autochrom system is different from a conventional sublimation heat transfer system and itself is colored, thereby it is not necessary to prepare a ink ribbon or ink cartridge other than the recording material. In addition, a protection layer is provided on the top of the recording material in order to provide a high resistance against affects from the external.
In a Thermo-Autochrom system printer, a thermal head first provides a heat energy to the heat-sensitive recording material to color only a yellow layer. Then the yellow layer is fixed by a phototube emitting a light of wavelength specified for the yellow layer. The thermal head next provides a heat energy to the heat-sensitive recording material to color only a magenta layer. Then the magenta layer is fixed by another phototube emitting a light of wavelength specified for the magnet layer. The thermal head finally provides a heat energy to the heat-sensitive recording material to color a cyan layer, then the heat-sensitive material is discharged to complete a full-color printing.
In the photo-fixing described above, when a light amount for a coloring layer is less than required, a desired color is not obtained because the coloring layer is colored again when the next coloring layer is colored. For example, when a light amount of the phototube to fix the yellow layer is less than required, the yellow color layer remains unfixed, and when the magenta layer is next heated to be colored, the unfixed yellow coloring layer is also colored. As a result, the obtained hue also contains a yellow component when the original data indicates only a magenta component, thereby resulting in more reddish hue.
In order to solve the lack of light amount, phototubes 111 and 112 are surrounded by a metal reflection plate 114 except for a side toward the recording material 113.
On the other hand, when a light amount for a desired coloring layer is more than required, the next coloring layer is sometimes fixed during the desired layer is fixed. In this case, the magenta layer is not colored enough when the heat energy for coloring the magenta layer is provided.
Therefore the emission light amount of the phototube is adjusted by measuring the light amount during the photo-fixing processing in order to always obtain the desired light amount. A light sensor such as photo-diode is used to measured the light amount. The light sensor is attached on the metal reflection plate 114 along with the sensor circuit.
However a harness is needed to attach the phototubes 111 and 112 on the metal reflection plate 114. Another harness is further needed to attach the light sensor and the sensor circuit on the metal reflection plate 114. The number of components are thereby increased, resulting in a higher cost and a more assembling processes.